baumann



K. SAUMANN. STEAM TUHBINE.

APPLICATION FILED .IAN.201 I92T.

Reissued Ain-L26, 1921.

15,092. 5 SHEETS-SHEET I.

/far/aumgsgg ATTORNEY K. BAUMANNx STEAM TURHINE.

APPLICATION min Mmm. 1921.

Reissued Apr. 26, 1921.

K. BAUMANN.

STEAM TURBNE.

APPLICATION man JAN. 2o. 192|.

Reissued Apr. 26. 1921.

f'fg.

lar/@maggy "Y Il my K. BAUMANN.

` STEAM TURBINE.

, APPLICATION FILED muze, I92I.

R M Wa /r E Z s. o f 2., x m I M .4h U m w r/ 2 .2 0 5 a I B 1w *I A 4#nu a I 1 42 W DIM, @//m/ L 2 9 1 6., 2 um., A d .HD u n M UNITEDl STATESPain-:NT OFFICE.

KARL BAUMANN, OF URMSTON. ENGLAND, vASSIGN'OR TOMETROPOLI'TAIN-VICKERS yELECTRICAL COMPANY, LIMITED, A COMPANY ORGANIZED UNDER THE LAWS 0FGRE'AT BRITAIN.

STEAM-TURBINE.,

Original No. 1,302,282, dated April 29, 1919, Serial No. 105,409, filedJune 23, 1916.

l reissue filed January 20,

The invention has for its object to pro? vide an improved turbine oi.this liind in which certain constructional dit? ities inherent in a.turbine of this type are overcome in a novel and l'n-:ictical manner,and the output for a turbine of a given speed. and efficiency isconsiderably increased.

As is well known, the maximum output which can be obtained -in any giventurbine is determined by the' blade area through which the steam leavesthe tin'bine proper. This blade area is limited by thel practicaldiiiiculties which are encountered when blades above a certain length:we used.

In some cases the outlet angle of the blades has been increased in ordertoobtain the necessary area for the. steam to fiow through. Thisarrangement, however, impairs the eiciency. of theturbinel The laststage or stages of the turbine Ahai e also been constructed as' a doublestage 'or stages, one-half only of the steam acting in each half of thedouble stage.. In this arrangement the 'steam -in the last stage orstages flows in opposite directions necessi tatlng large and complicatedpassages for guiding one-half of the steam from the pre ceding stage toone-half of the divided laststage vor stages,'and for leading theexhaust steam to the condenser. With this construction the cost of theturbine is consider ably increased and losses are caused by theformation of eddies in the steam during its `flow through theA guidingpassages.

According to the present invention theturbine is so constructed that thesteam flow- `ing in substantially .the same direction Speeication ofReissued Letters Patent. Reissued Ahpr, 2.6, 1921,

'Application -for 1921. Serial No. 438,743.

tical effec-t one or more of the rows of both stationary and movingblades or of a row of moving blades in a low pressure stage or stagesot' the turbine, for example, the penultimate and ante-penultiiiiatestages, is or are constructed in lnultipletieis or rings` the individualtiers in a row of 'blades being separated from each otherby"circu1nferen tial divirfling walls, so that the steam iiowng throughsuch rowor rows of blades is segre gated into two or more annularportions or helts, the steam flowing through the blades in an outer tieror tiers being expanded. at a greater rateat cach stage (comprz ing arow oi' guide blades or nozzles and its cooperating row or movingblades) than that at which the steam is expanded which flows through theblades or vanes of the adjacentr inner tier or tiers of the same row orrows lying nearer the .turbine shaft'. i

Vith the rows of blades provided with dividing walls as aforesaid, thesteam leaving the outer portion of a row of moving blades will insoinecases have'. been fully expanded and passes either direct to the eX-haust or through one or more vfurther rows of moving blades in which itsremaining velocity energy is abstracted. The steam 'leaving the adjacentinner portion of the same row of blades will notl have been fully`expanded and may either .be further expanded in a final row or rows ofundivided or divided stationary and moving blades from the latter ofwhich it flows to the eX- haust. or may be further segregated into oneor more portions in one or more succeeding rows of binding some only orall of which are provided with dividing' walls, the outer portion orbelt of steam leaving the Inoving blades of sonie or all of suchsucceeding row or rows passing direct to the exhaust, tlul inner portionof steam' from thc last divided row oi' blading passing to a final rowor rows oi binding in which it is fully expanded and therxfe to theexhaust. It will thus be seen that the steam in au outer tier or tiersis expanded at a greater rate than the steam passing through an innertier or tiers oi the same row or rows of blades.

The arrangement above described in which the rows of blading are`rprovided with tir-` cunifereutial dividing walls so as to form mumefficiency in that tier but with the object of securing the flow ofalarge amount of ste-.ini through such inner tier, at the same time-mantaining the mechanical strength necessary to support the outei` tieror tiers of moving blades. This can b e done either bnot'expai'uling'the steam far enough to olitain the besteliiciency or byincreasing the outlet angle of the binding or in both of these ways.

I have found `that a very satisfactory way of accomplishing the aboveobjects is to ernn ploy blading of the reaction type in one `or more ofthe tiers and of the impulse type for the other tier or tiers of thesame row or rows of biading. For example. for the `iii termediaterows ofbinding where considerable differences inthe rate of expansion-oi thesteam in the varioustiers take piace, I prefer to ilse blading of thereaction type fortlie inner tier or tiers and blading of'tlie impulsetype for the outer tiers. Blad-ing of the reaction type may also beadopted for the inner tier or tiers and ot' the impulse type for theouter tier or tiers of the final row .or rows of blades. y

The use of dividing walls which separate the binding of a` row intotiers is.` not re` strieted in its use to the iiiterniediate row or rowsof blading, `wlieie the pressure of the steam leaving the blades of theseveral tiers varies, but may also tor structural reasons beadvantageously employed in the final rowy or rows ofghiading where `thepressiire at "which the steam leaving the biadesis substantially uniformover` .the whole of the blade area in such'tinal row orrows.

In somecases it may bedesirabie. to design the binding 'in the innertier or tiers of the' intermediaterows to torni guide passages only forthe steam, the pressure and velocity of the steam heilig substantiallyvse (i il the same'at the entry and exit ends of Va. stage. In othercases the pressure of the steanimay be reduced and its velocitycorrespondingly increased Without, however, ab-` stracting any of itsenergy while passing of the flow of'steam ytakes'place during its-vpassage throfngh the statioi'ary blades ot the inner tiers, in` whichcases sonic or all ot such liladesinay be. omitted.

The invention iiiay` be carricil into e'cct n in a variety of ways,sonic ot which will now be Idescribed witlrreference `to the acicompanying drawings. in which ligures lI and 2 are conventionallongitudinal sections' of the upper half of turl'iines of the impulsetype constructed in accordance with this invention. Fig. 3 is a parto-fa view similary to those ot' Figs. l and 2, showing the inven-n 'tlonapplied to a well known type ot reaction turbine, and alsoA illustratingsections of parts of the binding. Fig; l isa sectional view of a turbinein wliiciil the high pressure. stages are of the reaction type. and inwhich the low pressure stages are ot' the well known -diskconstruction,the bladiiig being either .ofthe-reaction or `of the ini-pulse type.

Fig.` ,l 'i isni sectional view on an enlarged scale ot' the hladingonthe line \''-\v of Fig. 1.

Fig.` (i is a similar view of the blading on the line Vjl-VI' otFig. l.Fig. 7 is a fragmentary reliroduction ofithe last rows' of the bladingot the turbine illustrated in Fig. 2, Figs. H. l), l0 and il beingsectional' `views respectively on the lines VIH-VIII, IlX-IX7 XX,XI-XL'of Fig. 7. Fig.

yFigs. l to et. -tionai view hereinafter explained.

througgghl the inner tier or tiers of bladinfr.

1.2 is a sectional view also on an enlarged scaleot' an alternative formof -bladingl which may be adopted in place ofthosc shown in Figs. 9 andi0, or ot' the final row of stationary blades shown in Figs. (i and il.Figs. 13,14 and `i5 are fragmentary views showing in section alternativeforms of binding which may be used in'the inner tiers of bladiiig in theturhiiies shown in Fig. 16 is a detail construe` Fig. 17 is a detailview of Figs. 18 and if) sections on the lines XVliI-XVIIL XIXe- XIXrespectively ofr Fig. 17 hereinafter explained. Figs. 2l), 2l, 2:2 areenlarged detail -views showing various forms of packingr` which may beemployed between the stationary and inovingblades. Fig. 23 `is afragmentary diagrammatic illustration of another form which a turbine,Vto which .tliepresent invention is applied, may take. Similar parts areindicated by the saniereterence numerals in the various figures of thedrawings. 1 y

Referring now to Figi l, the turbinevcylindei is indicated at l and theexhaust casing at 2. vllheturbinc shait is indicated at 3 and the steaminlet at 4. Theeinlet nov# zles" are shown at 5 and the iirst wheelat--G 'i l'irovid'cd with moving blades. 7 as usual.l

Said nozzles and niovinggbladcs comprising the ii rst stage aresucceeded by further rows ot' stationary nozzlesa, 8 and movingbladcsf), 9, forming subsequent stages in the uslial way. The row `oflstationary .blades-10, 1-1 into inner and o vdiaph ra blades 10 andcoperatingmoving blades 11 are each provided with a circumferential wall12, 13 respectively, whic divide the er portions. This dividing wall maybe formed by providing the/blades with lugs or flanges at anintermediate point in their length. The outerportion of the blades 1U,11, forming the outertier, namely that tier lying far' thest from 'theturbine axis, is designed so as to. expand the steam flowing through itat argreater rate `than thatgtr which the steam flowing through theinner tier of these blades, namely that tier lying nearer the turbineaxis', is expanded. The stationary andv moving blades 10, l1 arefollowed by a further row of stationary blades 14 and cooperating movingblades 15, the former being here shown as consisting of two portions, amain portion 22 and an outlet portion 23. As. illustrated, thestationary blades 14 are supported in position in a 16 which is held inposition by means o lugs 17, 18 engaging with a .we

19 extending between the turbine cylinder 1 and a guide-wall 20 in theexhaust casing 2. 'The outer ends of the stationary guide blades 14 inthe diaphragm 16 are provided lwith an inclosing wall or rim 21 whichseparates theI steam passing through the stationary blades 14 from thatleaving the outer portions of the moving blades 11.

'17. e operation of the turbine, constructed as above described, is asfollows:

The steam admitted through the inlet nozzles 5 flows through the movingblades? and then passes through the several stages t5, 9, 8, 9 and so onin succession in the usual way until it reaches the fixed guide blades11')'and.moving blades 11 where the steam is divided into two portionsby the circumferential walls 12, 13, the outer portion of steam, namelythat flowing through the portions of these blades lying farthestvfromthe turbine axis, being expanded to the pressure in the exhaust. of' theturbine, and passing from the outer portion of the moving blades 1.1direct into the exhaust casing 2. The inner portion of steam. thatflowing through the portions of' the blades 10, 11 lying nearest theturbine axis, only partially expanded and after leaving the innerportions of the moving blades 11 passes through the stationary guideblades 14 and moving blades 15 in which the steam is fully expanded, andafter leaving the moving blades 15 also passes direct into the exhaustcasing 2 of the turbine.

The steam leaving the inner portions of the stationary and moving blades10 and 1,1 is thus at a higher pressure than the steam leaving the outerportions of said blades and it is necessary therefore that theclearancespace between the circumferential guide wa1ls-12and 13 andbetween the cireumf l dirert'ions.

.bla ing fcrential guide wall 13 and the outer rim 21 ofthe diaphragm16. should be as small as possible. This is best effected by means of athrust block located as near as possible to the low 'pressure stages andby providing,

the edges'of the circumferential-wall 12 and of the rim 21 with glandstrips, several forms of which are hereinafter described and shownin.Figs. Q0, 21 and 22 of the drawings.

f It will be `seen that with a turbine constructed and operating asabove described, constituting what may be termed a multiple exhaustturbine, the total area of the moving blades through which the steamleaves the turbine proper is that of the final row of moving blades 15plusI the area of the outer portion of the moving blades 11.

In this way the desired increased leavingv blade area necessary in orderto secure an increased output is obtained without nervessitating theemployment of a final roti? of moving blades of inordinately greatlength or of a divided stage or stages through the blading of which thesteam flows in opposite Alternatively, for the same output a smallerblade angle can be utilized for the leaving vstages than with aturbineas heretofore constructed having but a single final row of blades of thesame blade height, and thus a better efficiency for the leaving stages,and consequently for the whole turbine, can be obtained.

The energy extracted per unit wei ht of steam in the outer tiers ofstationary lades l() and moving blades 11 will be approximately equal tothe energy extracted per unit Weight of steam passing throu h the innertiers of stationary blades 1() an mov` of stationary blades 14 andmoving'blades 15. In the construction illustrated, the steam flowingthrough the inner tiers of stationary blades 10 and movin blades 11 `isexpanded at a lower rate t an is the steam flowing through the outertiers of sta.

tionary blades 10 and moving blades 11, the

remainin expansion of the steam flowing through t ie inner tiersof saidblades taking place in the guide blades M and movin blades 15.A The meanperipheral speed o the outer ti of movin blades 11 is considerabl r" terthan t e mean peripheral speed o die moving blades 15, consequently agreater amount of expansioncan eilioiently be utilized in said outertier; in fact the expansion can be distributed in Suche manner that theefciency of said outer tier may be higher than that ofthe final stage14,15. y

Figs. 5 and 6 are sections drawn to an onlar ed scale showing onearrangement of which maybe used in the final stagesY of theturbineillustrated in Fig. 11.

Referringito` Fig. 5, the guide blades-8v and moving blades .9 aswell asthe outerv tiers of the blades 10, V11, are of the usual impulse type.In'VFig. 6 'the stationary blades h and moving blades'9 are, of course,fthe samedis the blades 8, 9 in Fig. 5, where- `asthe stationary 'blades1() and moving blades v11 of the inner tiers of those blades are cfatype specially designed with a. View to 'passing a large quantity ofsteam through the available blade area, by which terni is meant thetotalarea of the complete ring of 'blades measured on a plane'`perpendicular to .the shaft. The inner tiers of the blades.

10, 11 are also designed for a. relatively:I small expansion only of thesteam flowing.-

through them, and also with a view .to pro- -viding the moving blades`vvitlrtlie necessary mechanical strength'.` Ir onder that a largequantity of steam ma`r through them the blade anglesiad opted' for "ftheblades of the inner tiers, ar;consider ably greater than the bladeanglesadoptedy The 'expansiou`- in they `inner tiers of this stageoccurs mainly in the moving blades 11 in which the steam,v

velocity is increascd. beyond that .existing 'f for the outer tiersinthen inner tier ofthe guide blades 10, as the space between the movingblades is reduced on account ofthe thickness which it is desirablevtogive to the inner-'portions of said blades to afford the necessarymechanical strength. i i

In order to obtain the maximum strength of the blades for a-giveii steamvelocity it is necessary yto arrange that-the` expansion shall takeplace 'chiefly at the entrance of thcpassages betweenthc moving bladesl1,

yand that the velocity vshall remain practically constant while thesteam is passing through the remaining portions of the pas sages betweenthe blades, the lea'iiiiig angle being arri-.bied as slioivii in Fig. (3so that the width ofi the remaining portions of the 'y passages betweenthe blades is practically constant. f The final rows of guide blades14and moving blades 15 are, as slioivn in Fig. G,

-of the usual type as regards the blade an- It is, however, necessary togles employed. increase th `width of the guide blades 14 andconsequently the distancefbctween the moving bladesall and 15, in orderto avoid tlieiformation of eddiesand obtain a satis.

factory flow of the steam passing through said guide blades, aswell asto provide the necessary space for the stesi-iii4 leaving the outer tierof moving blades 11. In the construction sliown in 1i and '6; the' guideblades 14 consist of tv'o portions, namely main portions 22 which. inthe construction showinare cast in one -piece with .the diaphragm 1G,and outletjportioiis 23,

which are preferably formed separately` and either cast or afterwardinserted into a Y passed frame 39 forming .parto'f the diaphragm 16. Thestationary blades 14 need not, however, necessarily be' constructed intwo portions, as shown in Fig. 6, but may be formed as slioivn insection in Fig. 12, iii one piece.

. In some cases, in 'order to provide the nec-` essary strength themovin blades 11 and the `final roWof movingikb ades V15y may be made totaper in Width asshovvn in Fig. 1, or in thickness, or in both o'thesedimensions along the Whole ora portion of their length, increasingv insection toward thel root of the blades. Advantageonsly these blades maybe constructed as described 'in the specitic-ation of British Patent No.14,051 of Oc- 4tober 4th, 1915.

VAlternative designs for the inner tiers of stationary blades 10r andmoving blades 11 -slioivnhin Fig. 6, which in certaincasesA ,may beadopted, are yillustrated'in Figs. 13, 14: and 15.y

Fig. 13 shows a de "en in -wliich the oiitlet angle of the guide blades1() is' smaller than in Fig. Gand is such that having regard to thevelocity of the moving blades 11,relativeto that ott-he guide blades 10,the steam enters said moving blades in an approximately axial direction.In this design' a` relatively greater partl of the expansion occurs intlieguide blades 1() than in the corres r)onding guide blades 10 shownin HFigIG." rlhe inlet portions of the moving blades 11 are reduced toan edge vas showin,

so as to prevent eddies where the steam meets the edges of the blades.The expair sion through the moving. blades 1l .takes -place chiefly atlthe inlet portion of the moving blades y,1170i Fig. 13,.the lleaving iangle being arranged shown so-that the width of the remainder of thepassage be- Jv,tween the blades remains practically con- Stai'it.

In the design shown in Fig. 14 no change in the direction of the steamtakes place Iduring its passagel through the guide blades 10. Y

The blades can, as shown, be flat and located in a plane parallel withAthe axis 'of the turbine, or they may be inclined iii either `directionwithv respect to the turbine axis.

As no appreciable `bange in the direction of the `steam takes p ace someor all of the blades 10 `may beomitted. If these blades are omitted thevelocity of the steam may be varied as desired either by decreasing orby increasing the-radial height of the passage.- If the inner tier `.ofguide blades is omitted soine means for directing the steam flowing fromone row' of moving blades to the next, to take the .ilace of the innercircumferential wall of the guide passages,

' Lapseare designed in such .a manner that no eit-A pansion of the steamduring its passage through them takes place and the direction of thesteam leaving is the same as the direction' of the steam entering theblades, no mechanical energy being abstracted from the steam'du'ring itspassage through them, and lconsequently no appreciable change in itspressure occurs. The moving blades 1] are of an f shape, as shown, thecentralportion being straight and of uniform thickness, and the sidesreduced to an edge so, that the steam passage between two adjacentblades is of practically con-I Stant width. .This design enables bladesof the necessary mechanical strength to be pro- "ided which do Anot'chane the velocity vof the steam to any extent uring its passage betweenvthem.

The lguide blades shown in Fig. 15 are of the same type as those shownin Fig. 14. The moving blades 11 are flat and more orless.inclined'relative to the axis of the turbine, being reduced to afine edge at bot-h sides, especially at thel outlet side, the centerportion of the blades being preferably'r of substantially uniformthickness.

. A passage is thus formed between adjacent blades -in which thepressure ofthe steam is reduced at the entrance of the blades and thevelocityr increased as it flows toward the middle portion of the passagethe vclocity being reconverted into pressure byj `final row may take.described ab'ove with reference to Figs. 5, 6, 12. 13, 14- and 15,havebcen given by way ot' example and as indicating some otl the iuoreadvantageous designs which can be employed. The blading ot thecircuniferentially 'divided tiers niav sometimes be ol' thel samecharacter in.

two or more of the individu-.il tiers of a row. The expansion howevertaking place at difl'rrent rates'in l'lie'several tieis of a row. `Theblades may in some cases also have the same inlet and outlet angles inthe various tici-s ot' a row. Frequently also it ywill be fiiundadvisabh` to provide an outer tier of a row with a greater number o fblades vthan an inner tier of thc same row.

Fig. 1G shows a modified form which the outer inclosing wall of thestationary blades may, with advantage, assume. The' outer wall or rim 21is here shaped so as to change -tlie direction loff the steam leaving`the outer tier of the moving blades 11 from a substan-` tially axialinto a substantially radial direcl 'tion during its passage to theexhaust casing. In order to prevent, as far as possible, the formationof eddies, due to the rapid change of direction of the Steam, anadditional guide 24 may be provided which will separate the steamflowing to the exhaust into two 'portions. More than one of suchadditional guides may of course be used if desired, and they need notnecessarily be su ported from the inclosing rim 21, as hereilliistrated` but may be attached to the' turbine cylinderor exhaustcasing. One oi" more simliar guides to that shown at 24 in Fig. 16 maybe provided for directing the steam leaving the last row of. movingblades 15. The shape given -to the inclosing rim 21 and curved guide 24will obviously depend upon the direction in which it is desiredthe steamleaving the moving blades should flow toward the exhaust, as the changein the flow of the steam need notnecessarily be from an axial into aradial direction. l l

Fig. 17 shows a further modified construc- Ation' oi the final guideblades 14 and moving bladesl. an additional circumferentialdividing wall25 being provided extending ,over a part or the whole width of theguideY blades 1l and corresponding dividing wall` 2G separating themoving blades 15 into the inner andouter tiers. The stationary .andmoving blr desfof the outer tiers are again of the impulse type andthose of the inner tiers are of the `reaction type. The blades of theinner and outer tiers are respectively shown in section in Figs. 18 and19. these fiifures being taken on the lines XVIII-X vIll', XIX-XIX ofFig. 17. This combined use of impulse and reaction blading in one andthe same row is, in some cases, also adapted to obtain the bestefficiency for the last stage of the turbine'. as well as mechanicalstrength for the roots of the moving blades, blading of thi` reactiontype. being more suitable for the inner tier owing to the relativelyhigher steam velocitiesobtained in the passages between the movingblades which enables the i'oots of the moving blades to be made ariseldue to the great 'dilerence in steam velocitiesresulting'from the greatdifference in the peripheral velocities between the inner and the outertier.

Iig. shows on an enlarged scale"v the type ofvpacking shown in Fig. 1 asbeing' i used between the circumferential dividing 'walls ot' the`stationary rfid moving blades` 10, ll .and between the moving blades 1land the inclosing wall 21 of the stationary blades 14'.. As shown inthis figure the side of the circumferential wall 12 adjoining thecircumferential wall 13 is sharpened to a. knife edge so as to reducethedaiigcr'of heating in case rubbing takes place between'tlie walls 12 and13. The nclosing rim 2l is shown as being provided with a gland strip 27of a well known type `for a similar reason.

Fig. 21 shows an alternative form of pack? .the same. direction as theworking steam Y' passing through theftiirlgi'ine.V The `directionvolumes of Asteam. through ,the low pressure ,stream lines.

in which any leakage steatn willhejcaiised to How with` -the arrangementshowrfijzin this figure is indicated.diagrammatically bythe Referringnow d l v struction which may be adopted nin .those cases wherey it isnecessary to .pass greater' stages of the yturbine than in the case ofthe vturbine describedy with refereneelto Fig. 1. i In other words, torsimilar steam yconditions and eicieneies the outputof the turbine can,with this construetion, lbe considerably ini creased. ln the turbineshown in Fig. 2 the i at steam flowing through the innerv tiers ot'.Vthe circumferentially Hdivided stationary i and moving `blades 10, 11'is further segregated by eirr-,iimferential division walls 31, -32 inthe succeeding stage comprising a row of fixedbladesi andmovi'ng blades34. The steam passing, through the outer tier of the stationary; andmovingV blades 33; 34 is expanded .down tothe pressure inthe Vexhaust towhich it directlyowson leaving the outer `panding at a low rateduringvits passage through the inner tiers'ot the stationary andmovingblarles 33,34 is again segregated into `two portions by`circumferential dividing walls 35, 36 in a further succeeding stagecomprising stationaryiind movingblades in` dieated at 37,`38,respectively. l"llie'fstcain ai Fig-,2, aus Siiws a et passing through theoutertier of the station` aiv and moving blades 3T, 88 isrexpanded downto the pressure of the. exhaust and on` leaving the outer `tier ot'moving blades 3S passes direct into the exhaust casing 2. The .energyYremaining in the steam ai'ter flowing tliroiiglithe inner tier of thestationary and moving blades 3T. 3S iii wliicliit is expanded ata lowrate is utilized in a final stage eom, prising" stationary blades 14 andmoving blades 15 in a manner already describedwithv reference to Figi; j

It will `be seen that iii a turbine constructed as shown in Fig. 2 thetotal blade area 'through which the steam leaves the turbine proper isaiiproxiniately increaseul` by the blade areas of the outer tiers of themov ing bladesl and 38' ascompared with' the construction illustrated infFig.A 1.

()ne arrangement ot b lading which may be adopted `in a turbine ot' thckind illustrated in Fig. .2 is shown for example in Figs.` T to 1l.inclusive. Fig. T it will he seen is a reproduction of some ofgtlie lowpressure stages of Fig. 2 and Figs. 8. 9, 10 and 1"l are'sections oftheblading in Fi 7 taken respectively on the lines VIII-VFIL IX-lX, X--Xand XL-XL The maiiiier in which the'tui'binedescribed and illustrated iuFigs. T. B. 9, 10 and l1 operates will be readily understood from whathas been lsaid in connection with Figs. `il, 5, 6 and 12-` it beingunderstood that intlie `turbine illustrated in Figs. 2, 'i'. 8, 94, 1()

and 11 also various alternative designs and eombinationsoi bladng may--be, 'used las liereinbefore fullyset forth.

One: example ofliow the invention may he applied to a turbine inwliiclithe whole of Vthe binding is of the raction typedsilliis trated ilu Fig.3. the construction and operation of \\'liicli.iaken in conjunctionwith` the sectional views of the bladin'g in the low l )ressure stagcsonthelinesl-l. ll-Jl and and designated b v vthese.numerals respectively.wi'll be easily .comprehended 'without further detailed' description.

Fig. 4 illustrates still another form of. turbine constructei'l'inaccordance. 4with this invention in which the high pressure stages areof the usual Vreaction type and the low pressure stages are 'of the well`known disk construction. "the bliiding being of either the impulse 'orreaction type or a combination' of these types.`

In tlieconstrnction illustrated in Figs. 1,

2" and 4 the 'moving blades of the low presd sure. stages are vshown asbeing `attached to separate disks mounted on the shaft 3. In some casesitI is preferubleto attacl'i some or all of such moving blades directlyto the shaft itself. the shaft `in, such cases bein increased iiidiameter iand^`"provided .wit i Hai'igcs or colla rs vto whicli'tliemoving blades are secured iu any suitable way. ln thesetik a irisfiguresalso a single .exhaust casing only is shown into which the steamleaving the several rows of moving bladespasses. It is Vto be.understoodhowever that the steam leaving the various rows of moving'blades ma)vpass to separateexhaust casings and in some cases to separatecondensers. ifn desired.

A still further constrnctional form which the invention may take isshown diagrammatically in Fig. 23. In the turbine dia rammaticallyindicated in this figure it will be seen that the segregated annularportions of steam each flow through a plurality of rows of fixed andmoving blades before reaching the pressure of the exhaust and iassing tothe exhaust casing of the turbine. t will also be observed that in onerow-of stationary and moving blades the steam is segregated intothreeannnlar portions, the stationary and moving blades in questionbeing constructed as a triple tier. The blading may be arranged in sucha way that the ratio of the steam velocities andperipheral velocitiesobtaining in the various tiers is apl'i'roximatel)` constant, thus,obtaining a uniform elliciency -over the whole of the various. noirs ofblades.

From the examples hereinabove described and illustrated it will beevident that the steani flowing through the working passages of a tibineconstructed in accordance with this invention is dividedinto separatepor- "ftions forming more or lesscomplete and turbine.

partially overlapping belts of steam, the ontermost belt or belts whilepassing through theoperative bflading of the turbine being expanded at agreater rate than the. inner belt or belts lying nearer the axis .oftheThe steam in the outer belt or belts is let away separately to theexhaust immediately it has been expanded to the full extent. and itsvelocity energy abstracted therefrom. M V

Stated in other-words the belts of steam flowing through the turbine.while in operation may he likened to a plurality of trillicated hollowcones. the steam forming the smaller end of the second and anysucceeding concs being derived from the steam of the preceding cone. Atthe, base vot each of such cones the Steam will' have been fullyexpanded 'and conducted away to the exhaust. Thus the steam will be ledaway to the exhaust from a plurality of independent rows of movingblades. v

As hereinabove set' forth turbines of either the impulse or reactiontype, or a combina tion of those types. may be constructed in accordancewith this `invention and although the invention is an improvement inturbines of the axial flow type it is to be understood that. the highpressure oir other sections of the nrbine to which the invention is nota plied may. if desired be of any other suit a le type. The;` inventionis especially apexhaust.

2. In a turbine having a single exhaust. a 100' portions of the steamflow in opposite directions to the exhaust. In short, the invention maybe applied to axial flow steam turbines of many of the various existingtypes adapted t0 operate at a high vacuum in which, as heretoforeconstructed, in order to* obtain a large output, blades of inordinatelygreat length would have to be used.

In the modifications illustrated it will be seen that the low-pressuremotive fluid is segregated into a plurality of portions which dischargethrough successive rows of blading.' In this way, the leaving blade'areain the low-pressure part of they turbine may beblincreased to an extentheretofore impos- Sl e. l

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be per-y formed, I declarethat what I claim is:

1.' In a turbine, the combination of a 'plu. ralitv of successivelyarranged stages having the motive Huid passing therethrough inapproximately the saine direction including rows of moving .blades andmeans tn Aincrease the leading blade area including means to dischargesteam from-a plurality of said rows of moving blades directly to thelow-pressure part having the steam Howing therethrough in substantiallythe same direction including a plurality of successively. arranged rowsof moving blades and means .whereby steam flows from each row of movingblades directly to the exhaust.

3. A. fluidl turbine of the axial flow type in which the steam flowssubstantially in tha` same direction throughoutincluding a lowpress'urepart and means associated with the 110 low-pressure part for segregatngthe fluid into a plurality of Iannular portions and for expanding theportions at different rates, the portions passing from the plurality ofrows of moving blades vto the exhaust.

4. In a turbine. a low-pressure part includ# ing means for passing themotive fiuid thel` through in annular portions and in approxi..

-mately the same direction, the range of exv 5. In a turbine having ahigh-pressure 125. part and a low-pressure art, the'low pressure partincluding a. p umlity ofjsucsblades' and rged from sively arranged rowsof movi means to divide the steamedisc the high-pressure parinto aplurality of 130 Y abstracted from each ofthe annular portions.

Jia

portions, energy from each portion beingiabstracted by a separate row ofblades and all of theannular portions .fdnliarging to 'a common exhaustchamber.

6. In a turbine having a high-pressure part and a low-pressure, part,the low-pressure part including aplurality of successively arranged rowsof movin yblades and means to -divide the motive uid flowing from the'high-pressure part into arplurality of annular ortions or belts flowingapproxi mately in' t e same direction, energy being or belts b aseparate row of moving 'blades and all o the annular portions or beltsdisf charging into a eommonexhaust chamber.

7. In a turbine, the combination of a low pressure part including aplurality of rows of blades'and means for dividing" me of the rows intoinner and outer tierii and for segregating'the steam passingtherethrough into inner and outer portions, the inner portion orportions'passing tothe exhaust througha greater nuinber vof rows thanthe outer portion or portions.

8.l I'n afturbine, a low-pressure part havingthe steam,passingtlierethrou h in approximately thesame-direction inc uding inner tierblading, outer tier blading, and last row blading, the motive fluidbeing expand- `ed mainly in the Vouter tier and last row blading and theinner tier blading serving to' discharge motive fluid into said highexpension b ading. n

9. In a turb'ne, a 4 low-pressure' section comprising one or moresuccessively arranged stages including super moving blades, adapted todivide the motive fluid into a lurality of annular portions or belts anda sti-act energy from the lpelts` passing therethrough2 and other stage"or stages,

the inner portion or portionslof the lsuperpoaed blading adaptedtoy passsteam to said other stage or stages.

il). In a turbine, a low-pressure part coml prising a pluralityofsuccessivelyr arranged rows ofv stationary and'lmoving blades, andmeans associated with said blades to divide the steam vinto successiveannular ortions or belts for passage through successive rows off movingblades to the exhaust. i

11. In an axial flow turbine, a low-pressure part including a pluralityof rows of stationary and" moving blades arranged in succession and"means associated :with one or more of the rows of bladesf'to Isegregate"the steam passing ytherethrough into a plurality of' annular` portionsor belts which pass directly from `the moving rows of blades to theexhaust. y, 12. In a turbine, a low-pressure part hav- "ingthe motivefluid passing therethrough in substantially the same direction, a pairof rowsfof 'stationary and moving blades,

y means lto ydivide the motive fluid into inner` osed rows of and outerannular portions for `passage through the moving blades, a row ofstationary blades receivingthe inner annular ortion of motive fluid, ashroud carriedby the latter blades and cooperating with the turbine`casing to define :in exhaust for the i outer annular portion of motivefluid, said last-named 'blades being sufficiently wideto provide anadequate exhaust.' 1

13. JIn a fluid turbine, a low-pressure.part including a lurality ofstages inv which the motive fluid) flows in approximately the samedirection and means associated `with one or more of said stages to`divide it or i vthem into inner and outer tiers and to segregate motivefluid passing i therethrough into a plurality of annular portions orbelts,

the. annular portion or portions passingw through some tier or ti sbeing` expanded lat a greater rate than t e annular portion or portionspassing through the outer tier or tiers and the 4annular portions orbelts passing Ifrom the moving rows ofbladesv of said stagesdirectly tothe exhaust.

14. In anfaxial flow fluid turbine, a lowpressure part'including apluralityv of stages in which the fluid vflowsy in Substantially thesame. direction, circumferential wall or walls 4associated with thestage or stages to' divide the stage or stages .into inner and outer.Itiers and to segregatetlie motive fluid passing therethrough into alplurality of annular .portions or belts, the annular portion orVportions-passing through theouter tier or, .tiers being expanded at agreater rate than the annular portion or portions exhaust frq said.stages,i y. 15.'1n a turbine, a low-pressure part hav# ing the'mtivefluid` passing therethrough in approximately the same' directionincluding a plurality of rows of moving `blades and means Yfor dividingone or more of said rows into inner and outer tiers, the motive fluidbeing expanded at different ratesin the innerV and outertiers andpassing from precedin innertiersto succeeding outer tiers ya another rowof moving blades.

In the moving rows of blades of ing motive fluid passing therethrough inapproximately the same direction including moving rows of blades andmeans associated'fwith' one 0r more of said rows of blades. 'to dividekit or them intoinner and passing through the inner tier or tiers andythe annular portions passing directly to the iis 16. In a turbine, alow-pressure part havouter portions and to segregate the motive;`

lfluid into annular portions,

expanding in one blade1 rtion ata greater rate than in another an allofthe annular the motive fluid i portions of motive fluid being expandedto. exhaust pressure upon. discharge,fromA the 1 moving rows ofblades. i

17. In afluid turbine', a low-pressurepart having steam`flowingjwtherethrough injl sub#` stantially the same direction andincluding a plurality of rows of stationary and' moving blades, .one ormorecircumferential dividing walls associated with oneor more of 5 saidrows of blades for dividing them into inner and outer tiers andsegregating the steam Ainto two or more annular portions or belts, theouter tier or tiers adapted to expand steam at a. reaterrate than'l theinner 10.ti er or tiers, an said annular portions or vbelts passing froma plurality of moving blades tothe exhaust. 51x18.I In a fluid turbine,a low-pressure part jpeluding a plurality of rows of stationary l'ifgidmoving blades and ymeans associated ,"fwith one or more of said rows ofblades to di-Yide it or them -into inner and outer tiers and' tosegregate the motive fluid passing 'therethrough into a plurality ofannular 2Q portions, the annular portions passing through the outer tieror tiers being expanded at a greater rate than the annular lportionstiers, an all of the annular portions discharging 'from the rows ofmoving blades ditectl to the exhaust.

-19. n a fluid turbine, a low-pressure part including a plurality ofrows of stationary and movmgblades and circumferential walls eo atinwith a plurality of rows of said bla esto ivide the latter into innerand outer tiers and to .segregate the motive fluid passing therethroughinto a plurality of an nular portionsor belts, the blades of an outerhaving the outlet angles thereofdess than gl" theoutlet `angles of theblades of an inner whereby the `motive fluid 'will be ex- Plnded at agreater rate inthe outer tier .i than in the inner tier, and the annularporloztins'or belts passngffrom the moving rows 'i blades directly tothe exhaust. i n 20'. In a fluid turbine, a low-pressure part having'the steam assing therethrough in "',Stlbtantiall the saihe directionincluding a luralityo rows of stationary and moving i ladesand`circumferentia1 walls associated with a lurality of rows of saidblades to ,divide t ern into inner and outer vtiers and :lo segregatethe motive fluid passing there- .Q0 through into a plurality ofannularortions,

the blades of an outer tier being ci) the im- "ulse ty e and the'bladesof an inner tier o the reaction type whereby` motive will be expanded ata greater rate`in the 5 5 outer tier than'in the inner tier and theannular portions or belts of motive fluid .passing from the moving rowsof blades directly to the exhaust. 'i i 21.111 a fluid turbine, alow-pressure part having steam flowing therethrough in substantially thesame direction and comprising i a plurality of rows of stationary andmoving blades, 'means for dividingone or moreof. said rows into multipletiersandfor gating the therethrough dpassing through the inner tier or aplurality of annular portions, the blading i including a pluralitybfrows of stationary' and moving blades passing motive fluid iusubstantially the s'ame direction, means associated with said rows ofstationary and moving blades to divide the latter into inner and outertiers and to segregate thesteam passing therethrough into inner andouter 'annular portions or belts, and a last pair of `rows of stationaryand moving blades receiving steam from an inner tier, the steamexpanding in said outer tier or tiers and in said last pair of rowsbeing'at a dillerent rate than in the inner tiers.

23. A steam turbine vcomprising a casing, a rotor, one or more stages orsections carried thereby, a pair of rows of stationary and moving bladescarried thereby and receiving steam from the last of said stages, wallele ments associated with the stationary and moving blades to divide thelatter into inner-` and outer tiers rind Vto segregate the steam .intoinner and outer belts, thc outer tier of stationary and ymoving bladesadapted to cxpand and abstract energy lrom the outer steam belt, and asecond pair ot' rows ot stationary aiid moving blades carried by therotor and casing and adaptedto receive steam from the inner tier, theexpansion of the outer steam belt in the outer tier being approximatelyequivalent to the expansion ot' the inner belt in the inner tier and inthe second pair of rows of blading'.

24. In a -fluid turbine, a low-pressure part. including a plurality ofrows of .stationary andxnoving blades passing motive fluid insubstantially the saine direction, Incansassoi,

ciated With said rows of stationary and mov-i ing blades todividc thelatter into inner and Vouter tiers and to segregate the steampassingtherethrough into inner and outerI annular portions or belts, and a lastpair of rows of stationary and moving blades receiving steam from aninner tier, the steanrexpanding. in said outer tier or tiers and in saidlast pair of rows being at a different rate than in the inner tiers, themoving blades boing tapered from the roots toward the tips to providelblading Structure of relatively great radius and sullicient strength.

25. In a fluid turbine, a hiw-prcssure part including a plurality of'rows of stationary ,and moving blades 'passing motive fluid inSubstantially the same direction, means associated with said rows ofstationary and movblades to divide the latter into `inner and outertiers'and to segregate the steam passing therethrough into inner andouter annular portions or belts. and a .last'pair of rows of stationary'and moving blade sur..

last pair ot' rows beingr at afditferent rate than ln the inner tiers.all ot' the moving blades being tapered in thlrknessfrom the rootstoward the tips whereby relatively longV and adequately strong bladesmay be provided.

26. ln a Huid turbine. a'low-pressure part including a plurality of rowsot' Stationary and moving blades passing motive fluid in substantiallythe same direetion. means assoeiated with said rows oti stationary andmoving blades to divide the latter into inner and outer tiers and tosegregate the steam passing therethrough into inner and' outer annularportions or belts` and a last pair of rows of stationaryand movingblades receiving-steam t'roni an inner tier,

the steam expanding in said outer tier or,

4 ner and outer tiersi. and to segregate the steam passingtherethroughinto inner and "outer :mnularioortions or belts. and a last air of rowsof stationary and moving liledesv receiving steam `from an inner tier.Vthetsteam expanding in said outer tier or tiers and in said last pairot' rows being at a different rate than in theinner tiers. all of i themoving blades being tapered in thick;

nesse`1`1d'ln width from the roots toward the tips Iwhereby relativelylong!` and adequately outer tiers. and to segregate the steam into* aplurality of annular portions or belts, the outer tiers of a movingvrowof blades adaptedito abstract energy from an annular or tion andtheinner tier comprising b ado portions having their entryfedgs ta eredwhereby motive fluid is expanded whi e en tering between the bladeportions and the remaining portions of the blades defining l passages ofvapproximately constant width curved at the leaving'edges in order toseivng steam from :in inner tier. the steam expanding in said outer tieror tiers and in said and adequatelystrrmg blades ing therethroughin'toannnlar portions. the outer tier blading designed toA fully expandannular ,portions passing therethrough and the inner tier bladingadapted to pass steam to succeeding outer q tier bladingr and a lastpair of stationary` and moving blades with little loss in energy s0romprising stationary blade portions having large outlet angles andmoving blade portions having their entrance -edgestapered to defineentrance steam expanding passages and the remaining portions there# S5of defining 4passages of approximately conlstant width curved at thedischarge edges Y in order to secure' diseharge of steam in desireddirection.

30. ln aturbine` a low-pressurev part com? prising a plurality ot rowsof st'tionary and moving blades and means to. divideone or more ot' therows into inner and outer tiers and to segregate the steam passing."

-therethrough into a plurality of annular portions. an outer tieradapted to abstract energy from an annular yportion and dis" charge thelatter at exhaust pressure and an inner tier serving as a bv-pass for aninner portion whereby a .support for outer tier is L00- provided. v

.31. ln a turbine. a. low-pressure piirt. having motive fluidv passingtherethroughin approximately the same direetion int-hubA ing a'pluralityof rows ot' moving blades 105 and ymeans for dividing one or more ofsaid rows into inner and outer tiers. the inner tier serving to passmotive Huid withlittle loss in energy to succeeding outer tiers andanother row of moving bladesthe motive' 11o Huid being fully expanded innalned tiers and blades. v 32. In a turbine, a vl`o-w -pressure part`ineluding a 'plurality of'rowsgof' stationary and movingfblades', meansem'iperating with 115 some of said bladestodivide the steam vpass'- y.

ortions'. o .5 belts, the outer portions of t e moving said lastbladesserving to abstract energy from some of said belts' and the innerportions servinl 120 to guide some of said belts to suceeeding outerportions, and .rows of blades to abstract 'energy from last andinnerbelt 33. In a turbine, the combinatibnvwith elements supported bythe casing, the wall elements constituting walls cooperating tosegregate the steam into belts for the moving blades of the low-pressurestages.

^ 54. A steam turbine comprising a casing, a rotor, one or more stagescarried by the casing androtor, a pair of rows of stationary and movingblades receiving steam from the last of said stages, wall elements fordividing the blades into inner and outer tiers for inner and outerportions of steam, a stationary row of blades supported by the casingand receiving steam from the inner tier, a wall element carried by thetips of said last-named stationary blades, the wall elements coperatingto constitute a wall to segregate the steam into innerand outerportions, the outer tier of said moving blades'abstracting energy fromthe outer portion `of steam, and a row of moving blades coprating withthe last-named stationary blades for abstracting energy from the innerportion of steam.

flngi steam turbine having a casing and rotor, a low-pressure sectionincluding a plurality ofrows of stationary and moving blades, wallelements for dividing the blades into inner and outer tiers for innerand outer Aortions of steam, a diaphragm supported liy the low-pressureend of the casing, a stationary row of blades supported by the diaphragmand receving steam from the inner tier, a Wall element carried by thetips of said last-named stationary blades, the wall elements cooperatingto constitute a wall to segregate the steam into inner and outerportions, the outer tier of' said moving blades abstracting energy fromthe`outer portion of steam, and a row of moving bladescoperating withthe lastnamed stationary blades for abstractiiig energy from the innerportion of steam.

' 36. A turbine comprising a casing provided with an enlargedlow-pressure end, a rotor, a series of stages carried by the casing androtor, means for-segregating the steam discharged fromthe last stage ofsaid series into a plurality of belts or portions comprising wallelements, web elements connecting the Wall elements together and to theinterior ot the low pressure end of the casing. stationary bladesconnected to the casing and web elements, moving olades cooperating withthe stationary bl ides and carried by the rotor, andwall eler entscarried by some of said pairs ot blades, the wall elements carried bythe ends of some of said stationary blades, the wall elements of thepairs oit blades, the ends of the blades, and the first mentioned wallelements defining walls for the passage of belts of steam,and movingblade elements in` each belt to abstract energy therefrom.

nular portions, said annular portions pass` ing to the exhaust from aplurality of' moving blades, and meansassociated with the final bladesto divide them into portions having different blade outlet angles.

38. In an axial flow turbine, a low-pressure part having the motivefluid passing therethrough divided into a plurality of annular portionsincluding ont` or more wall elements to change the direction ol' flow ofone or more of said annular portions 'from approximately an axial toaplnoximately a radial direction and means cooperating therewith toreduce eddy effects.

39. In an axial flow turbine, a low-pressure part having the motivefluid passing therethrough divided into a plurality ot' annular portionsincluding one or more wall elements to change the direction of' flow ofone or more of said annular portions from approximately an axial toapproximately a radial direction and a circumferential guide cooperatingtherewith to reduce eddy effects.

40. In an axial flow steam turbine. a stage or section provided withmeans for dividingr the steam flowing therethrough into annular portionshaving different ratios of expansion.

41. In an axial flow steam turbine, a stage or section provided withblading structures so arrangedas to segregate the steam into separateconcentric annular portions having different expansion ratios.

42. In an axial flow steam turbine, a stage or section having bladesconstructed in nmltiple tiers and ai'rangcd so that the steam flowingthrough the different tiers will have different ratios of expansion.

43. In an axial flowstcam turbine, a lowpressure stage or sectionprovided with blading means formed so as to segregate the steam flowingthrough said stage or section into separate portions having differentexpansion ratios.

44:. In an axial flow steam turbine, ahigh pressure stage or sectionthi-ou rh'which the steam flows in one annular bo y and a 10W pressurestagev or section through which the steam flows in two or more .annularbodies having different ratios of-expansion.

45. In an axial flow steam turbine, a stage or section having bladesconstructed in multiple tiers formed so that the steam flowing throughthe outer tier hasa greater ratio of expansion than the steam flowingthrough the inner tier.

46. In an axial flow steam turbine, a. stage or section provided withmeans for segregatiiugr the stealp owing therethrough into separateportions having different ratios of oxpaasibli;y

X17; 1'n\an\axial flow steam turbine, a stage or section havingsuperposed concentric rags of blades so formed that the rings of bladesfarther from the `turbine axis have out et angles different from thoseof the rings`of blades nearer the turbine axis.

48. In an axial flow steam turbine7 a parytial peripheral adniisign highpressure stage and a fall peripheral admission 10W- pressnre stageprovided with h'ieans for segregating the steam flowing therethroughinto portions having different ratios of expansion. 1

Signedat Manchester th'l` 1"th day of December, 1920.

KARL BAUMANN.

